Zeolites SSZ-26 and SSZ-33 belong to a family of zeolites with three-dimensional intersecting 10- and 12-membered ring channels. These two zeolites can be characterized as members of a family of materials in which the two end-members are formed by the stacking of layers in an ABAB sequence (“polymorph A”) or an ABCABC sequence (“polymorph B”). The framework formed by polymorph A is of orthorhombic symmetry while the framework formed by polymorph B is of monoclinic symmetry. In between these end-member polymorphs, there is a whole family of materials that can be characterized by a fault probability (p) of 0%<p<100% (referred to herein as “SSZ-26/33 family”). Fault probabilities of 0% and 100% represent the end-members polymorph B and polymorph A, respectively. The aluminosilicate SSZ-26 and the borosilicate SSZ-33 are members of this family of materials and have fault probabilities of approximately 15% and 30%, respectively. Zeolite CIT-1 (CON) corresponds to a pure or nearly pure polymorph B.
U.S. Pat. No. 4,910,006 discloses zeolite SSZ-26 and its synthesis using hexamethyl[4.3.3.0]propellane-8,11-diammonium cations as a structure directing agent.
U.S. Pat. No. 7,648,694 discloses the synthesis of zeolites belonging to the SSZ-26/SSZ-33 family of zeolites using a structure directing agent selected from 1,4-bis(N-cyclohexylpyrrolidinium)butane dications, 1,5-bis(N-cyclohexylpyrrolidinium)pentane dications, 1,5-bis(N,N-dimethylcyclohexylammonium)pentane dications, 1,4-bis(N-cyclohexylpiperidinium)butane dications, and 1,4-bis(N-cyclopentylpiperidinium)butane dications.
U.S. Pat. No. 7,837,978 discloses the direct synthesis of aluminum-containing SSZ-26 using a structure directing agent comprising cis-N,N-diethyldecahydroquinolinium cations or a mixture of cis-N,N-diethyldecahydroquinolinium cations and trans-N,N-diethyldecahydroquinolinium cations.
The commercial development of SSZ-26 has been hindered by the high cost of these structure directing agents and hence there has been significant interest in finding alternative, less expensive means for the synthesis of SSZ-26.
Accordingly, there is provided herein a more facile and cost effective method for synthesizing SSZ-26 via interzeolite conversion of FAU framework type zeolites which can significantly reduce the amount of structure directing agent used.